Einleitung

Once upon a time I bought this amp used in a pretty bad shape, but that was exactly what I wanted - tinkering with electronics is fun, right? 😆

One of the issues it had was a malfunctioning noisy crackly volume pot. Today I'll show you how to replace it if yours has this problem too.

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    • If you're an experienced iFixer - it'll take you about 10 minutes to get it done.

    • Check the list of gear needed for this project. I offered the tools that I used but it’s absolutely doable with less or some other similar tools.

    • Important: disconnect an amp from the power outlet!

    • Please be careful - tube amps can hold a serious amount of electrical charge that can cause injuries or even death. Avoid touching any wires or contacts with your bare hands or instruments that have no reliable insulation.

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    • Let's start by removing the rear chassis screws. All of the screws we are going to deal with work nicely with a PH2 bit.

    • Then remove two side screws that also hold the amp chassis in place. Those are 4x30 mm btw.

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    • Below the chassis you'll find 4 more phillips screws holding a rear cover in place - remove them as well.

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    • Now it's time to remove the nuts on the input jacks and our broken volume pot - I used pliers to do that, but it is advisable to use a small adjustable wrench in order to avoid any unwanted scratches.

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    • Next let's remove the volume knob - you'll need a flat 2.5 bit for that. Carefully insert the bit into the hole on the rear side of the knob to undo a tiny screw inside of it.

    • That's it - chassis is free 👍.

    • Hint: use a plastic tray or a magnetic mat to safely store all of those screws and nuts. You can even write where all those parts come from.

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    • Slightly lift it up and pull towards you with just a hand to access the internals.

    • That's it - the amp's chassis is right in front of you.

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    • Disconnect the panel that holds the input jacks and our volume pot. For this you may either use your fingers or an IC Extractor/Connector Puller.

    • Then lightly push one of the input jacks inside of the chassis to remove the panel.

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    • Here's our panel safely removed from the chassis - front and rear view.

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    • Now let's replace a broken volume pot. For this we are obviously going to need a soldering iron, a flush cutter and a desoldering pump.

    • Hint - I used flush cutters to cut a broken pot off from the PCB and then used a desoldering pump to clean the mounting holes in order to get them ready for a new pot.

    • Also a good PCB holder may come in handy as you may see in my example.

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    • After removing a broken pot and preparing a PCB for the replacement put a new pot into place.

    • Add more flux - don't be shy there - and solder a new pot in place.

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    • Clean any flux residue with isopropyl alcohol and a cotton swab.

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    • Connect a fixed PCB to the amp's main board and assemble everything back together.

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    • Check if everything works as it should - plug in your guitar and adjust a volume - if it works and it's smooth and quiet...

Abschluss

...congratulations - you've fixed it 🏆.

in_sympathy

Mitglied seit: 01/07/13

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